AMATEUR scientist 83-year-old David Martin is so certain Sir Issac Newton got it wrong about gravity he's taking it to his grave - literally.

David, who thinks scientists were mistaken to accept Newton's theory of gravity, has had his own tombstone engraved to prove it. And he plans to leave every last penny in his will to maintain a library collection of books by the German Gottfried Wilhelm Leibniz whose alternative theory David subscribes to. But David, who lives on Austin Drive in Didsbury, says his wife thinks he's lost the plot.

"Like everyone else my wife thinks I'm mad and to be honest she prefers it if I don't talk to my friends about it.I started to tell her about the theories on a train journey once and she immediately told me to shut up."

The New Zealander has spent £2,000 engraving his headstone with a poem about his theories. It too is dedicated to the 17th century thinker who doubted Newton's scientific findings.

David's will states that all his money will go to Manchester Library to maintain its Leibniz collection if David survives his wife Doreen, who is 81.

He said: "Scientists have abandoned reason, they say that the universe is mainly empty but Leibniz saw that the Universe is absolutely full - like a fluid in which objects are driven by the heat of the sun and the other stars. It's not gravity that keeps the objects in place but the movement of the earth around the sun."

Now he believes his gravestone will act as evidence that he held the theory when it is finally recognised as the truth. He added: "I was determined that I wanted the truth to be told for posterity and I did not want some scientist coming along after I have died with a new theory that Newton was wrong but proved with a lot of complicated mathematical wizardry."

David believes the scientific community has deliberately kept Leibniz' writings - which have been published by Manchester University Press - in the dark.

He said: "I am convinced beyond dispute that gravity is all nonsense and Newton's laws are absurd."